Field of the Invention
Embodiments of the present invention generally relate to apparatus and methods for supporting a gas distribution plate or diffuser.
Description of the Related Art
Substrates in which flat panel displays are made from have increased dramatically in size over recent years. For example, a substrate which is typically divided to make a plurality of TFT-LCD flat panel displays had sizes of about 2,000 cm2 and have increased in size to about 25,000 cm2 or larger. Such substrates are typically processed in a plasma chamber having a diffuser. The diffuser is generally supported in a spaced-apart relation facing the substrate with a plurality of gas passageways adapted to disperse one or more process gases toward the substrate to perform a process to the substrate, such as deposition or etch. This increase in substrate size has brought an increase in diffuser size since the diffuser is approximately the size of the substrate.
Problems with current diffusers include sagging, creeping, movement, and/or cracking of the diffuser or associated components over time, due to exposure of the diffuser to high processing temperatures, to the forces of gravity, and to other forces. Such problems with current diffuser designs may adversely affect substrate processing uniformity and properties and may increase maintenance and replacement costs of the diffuser and associated components.
Therefore, there is a need for an improved gas distribution apparatus and methods.